List widget now supports injecting cssClasses

modules/backend/widgets/Lists.php

@@ -130,6 +130,11 @@ class Lists extends WidgetBase
      */
     public $treeExpanded = true;
 
+    /**
+     * @var array List of CSS classes to apply to the list container element
+     */
+    public $cssClasses = [];
+
     /**
      * Initialize the widget, called by the constructor and free from its parameters.
      */
@@ -176,6 +181,7 @@ class Lists extends WidgetBase
      */
     public function prepareVars()
     {
+        $this->vars['cssClasses'] = implode(' ', $this->cssClasses);
         $this->vars['columns'] = $this->getVisibleListColumns();
         $this->vars['columnTotal'] = $this->getTotalColumns();
         $this->vars['records'] = $this->getRecords();

modules/backend/widgets/lists/partials/_list-container.htm

@@ -1,3 +1,3 @@
-<div class="list-widget" id="<?= $this->getId() ?>">
+<div class="list-widget <?= $cssClasses ?>" id="<?= $this->getId() ?>">
     <?= $this->makePartial('list') ?>
 </div>